Loctite trouble

[BenTheRighteous]

I'm trying to install the astrosyn dampers I bought awhile back, but I've run into a bit of a snag - the belt pulleys are Loctited to the stepper motors and not coming off. I've removed both of the well nuts (if that's what they're called?) but the pulley is still holding fast.

I don't want to damage the stepper to get the pulley off. The internet recommends applying 550F heat, but a.) I'm not sure what that will do to the stepper, and b.) I'm not sure I can get the thing that hot with the tools I have on hand. Any other ideas?

[astroboy907]

Soaking in acetone might work...

[bot]

Did you use blue or red loctite on there? If it's red loctite, it will require heat to break the seal.

Otherwise, my advice is to use a shock force. Put the hex key in, seat it nicely, and give it a few good taps from a hammer. Directly down into the screw, not the direction you turn it. Sometimes shocking it can break the bonds.

[rpress]

A heat approach would be to use a soldering iron.

A chemical one would be to try methylene chloride, aka "Aircraft paint remover". It's strong stuff, use gloves and apply sparingly.

If you hit the shaft too hard it will damage the bearings.

[Earthbound]

If by "removed the well nuts" you mean the set screws (grub screws) are already out, ignore all advice about tapping the hex key with a hammer. Heat should do the trick. Might put the motor in the freezer for an hour, then remove and apply soldering iron to the pulley.

[Polygonhell]

If it was red loctite it's virtually impossible to remove without heat, either way your best bet would be to make up some sort of gear puller, you need upto apply the force between the base of the gear and the end of the shaft.
You do not want to apply excessive force to the shaft, either pulling/ pushing it into the motor housing or across it, it will damage the stepper motor.
On the plus side replacement steppers aren't very expensive, so if your break them trying to remove the gears it's not that bad.

[bot]

Oh I misunderstood his problem. The set screws are already removed? Hmm... heat, and carefull pressure is all I can think of. A few very light taps from a hammer on the pulley couldn't hurt, but yeah, be careful.

[jdurand]

Steppers normally have the shaft exposed at the rear to allow pressing on pulleys. Set the motor on spacers so there's support under that shaft, like a short bolt or something. Then you can use a press or small impact to break the pulley loose without putting any stress on the bearings.

Also, placing a socket over the pulley often gives clearance around the shaft to give you something to hit/press.

Once the pulley moves towards the motor, it should be a lot easier to pull off.

[BenTheRighteous]

Yep when I said "well nuts" I definitely meant "grub screws" - they were quite well-seated in there but did come out without a problem. The issue was that some of the loctite must've leaked between the shaft and pulley and bonded them directly. Luckily it was just blue loctite that I used though, not the red stuff (I didn't know there was a difference before yesterday!).

Unfortunately I already ruined one stepper motor. It was by stripping the mounting screw threads though, although I probably did a number on the shaft/bearings too by smacking it with a hammer and whatnot.

I think that since at this point I'm going to be ordering a replacement, I'll just order a gear puller as well and they'll arrive together. Thanks for all the ideas though!

[add1ct3dd]

It kinda recommends Blue for a reason, hope you get it sorted.

[geneb]

When I installed mine, I used a screwdriver and a small wrench (to act as a fulcrum) to carefully raise the pulley. All three of mine were loctite'd in place.

g.

[BenTheRighteous]

And the motor survived the ordeal undamaged gene?

[geneb]

Yep. I did it REALLY slowly and evenly. No hitting it!

g.